The Biology of Behavior

Unit 2: Biopsychology

Central nervous system consists of the brain and the spinal cord◦ Brain an organ of soft nervous tissue

contained in the skull; functions as the coordinating center of sensation, intellect, and nervous activity

◦ Spinal Cord cylindrical bundle of nerve fibers and associated tissue that is enclosed in the spine; connects nearly all parts of the body to brain

Peripheral nervous system made up of nerve cells that send messages between the central nervous system and all of the other parts of the body

The Nervous System

Spinal Cord

Spinal cord

Spinal cord anatomy

Neurons nerve cells that run through the whole body and communicate with each other.◦ 30,000 neurons can fit on a pinhead

Each neuron contains:◦ Cell body with nucleus◦ Dendrites : fibers that receive messages from other

neurons◦ Axons : fibers that send messages to other neurons

Neurons do NOT touch; there is a gap between them called a synapse

Messages are sent across the synapses by special chemicals called neurotransmitters

Neurons

Communication Between Neurons The use of

neurotransmitters causes an electrical current◦ There is enough

electrical current in the brain to power a flashlight

Major Neurotransmitters

Serotonin Dopamine Achetylcholine Norephinephrine Endorphins

Peripheral Nervous System Nerves : visible

bundles of axons and dendrites that extend from the brain and spinal cord to all other parts of the body

Responsibilities:◦ Sensory nerves - carry

messages from body to brain (pain, pressure, temperature)

◦ Motor nerves – carry messages from brain to body to respond

Voluntary Actions!!! Transmits sensory messages to the central

nervous system It is activated by touch, pain, changes in

temperature, and changes in body position The somatic nervous system allows the

body to move or change position It also sends messages to the muscles and

the glands and helps to maintain posture and balance

Somatic Nervous System

Involuntary Actions!!! Regulates the body’s vital functions, such as

heartbeat, breathing, digestion, and blood pressure

We generally do not have to think about these activities – they occur automatically and are essential for keeping us alive

Two divisions:◦ Sympathetic activated when a person is going into

action (“fight or flight”)◦ Parasympathetic restores the body’s reserves of

energy after an action has occurred

Automatic Nervous System

The Hindbrain: Medulla involved in vital

functions such as heart rate, blood pressure, and breathing

Pons located in front of the medulla; involved in regulating body movement, attention, sleep, and alertness

Cerebellum rests under the larger part of the brain (cerebrum); involved in balance and coordination

Anatomy of the Brain

The Midbrain: Located between the

hindbrain and the forebrain Involved in vision and

hearing Reticular activating system

begins in the hindbrain, rises through the midbrain, continues into the lower part of the forebrain◦ Important for attention, sleep,

and arousal

Anatomy of the Brain

The Forebrain: Thalamus serves as a relay

point for sensory stimulation; most of the messages coming from the sense organs go through the thalamus on the way to the higher levels of the brain

Hypothalamus located below the thalamus; vital to regulation of body temperature, storage of nutrients, and various aspects of motivation and emotion

Anatomy of the Brain

The Forebrain: Limbic system forms a

fringe along the inner edge of the cerebrum; involved in learning and memory, emotion, hunger, sex, and aggression

Hippocampus involved in memory processing

Amygdala involved in aggressive and fear based responses (fight or flight)

Anatomy of the Brain

The Forebrain: Cerebrum accounts for

70% of the weight of the human brain; surface is wrinkled with ridges and valleys, known as the cerebral cortex◦ Cerebral cortex is involved with

thinking, memory, language, emotions, complex motor functions, perception, and more

Anatomy of the Brain

Lobes of the Brain (4)

FrontalParietalOccipital

Temporal

Lobes of the Brain - Frontal

The Frontal Lobe of the brain is located deep to the Frontal Bone of the skull.

• It plays an integral role in the following functions/actions:

- Memory Formation

- Emotions- Decision Making/Reasoning

- Personality

Lobes of the Brain - Parietal Lobe

• It plays a major role in the following functions/actions:

- Senses and integrates sensation(s)- Spatial awareness and perception

Lobes of the Brain – Occipital Lobe

The Occipital Lobe of the Brain is located at the back of the head

• Its primary function is the processing, integration, interpretation, etc. of VISION and visual stimuli.

Lobes of the Brain – Temporal Lobe

The Temporal Lobes are located on the sides of the brain

• They play an integral role in the following functions:

- Hearing- Organization/Comprehension of

language